If the engine is running dangerously lean the whole plug tip will be grey or white. If the temperature is over 850-degrees, pre-ignition may occur. Engine power will be reduced and you risk piston damage.

Install each spark plug by hand until you have wound the thread a couple of turns. This reduces the chances of you cross-threading the plug. A typical copper spark plug will last around 20,000 miles and most get changed at a major service (usually around 16,000 miles) but an iridium spark plug will be good for around 50,000 miles and you do see people running them to 100,000 miles with no issues.

Spark Plug Removal

Most parts are pattern or aftermarket although some will be genuine but are not always stated as being so.

NGK is the brand leader in the UK spark plug market and are the world's biggest supplier to many major car manufacturers. Each and every one of their products are designed to meet the most rigorous standards and are the professionals' choice because of their quality and technical excellence. Their plugs can be found in use by teams in F1, WRC and MotoGP. Put simply, NGK genuine spark plugs are the workhorse at the heart of smooth-running engines around the world. You’ll need this to help you find the location of your spark plugs and how to access them. This may sound simple but often the manual offers up some time-saving tips for your particular model. If you’re going to be doing any sort of work on the bike, treat yourself to a decent set of tools. Most of mine are from the Halfords Advanced range (formerly called Professional).A regular spark plug uses a copper central electrode whereas an iridium spark plug uses, you guessed it, iridium. If you’ve not changed your plugs before, give yourself a couple of hours to complete the task. Here are the essentials you need for smooth re-plugging: The image of the spark plugs above shows four common conditions that you’ll find your spark plugs in. From left to right the plugs are Normal, Rich, Lean and Very Lean. Full descriptions below. The NGK Iridium IX Spark Plugs utilise a 0.6mm laser welded fine iridium tip which ensures high durability and a consistently stable spark along with a tapered ground electrode which minimizes electrical quenching effect. The longer insulator nose prevents fouling, the corrugated ribs on the insulator prevent flashover and a triple gasket seal eliminates combustion gas leakage.